This invention relates to apparatus and methods for quantifying gases generated or sequestered by plant life and photosynthetic organisms and to means for assuring that said plant life is an accurate and reliable bio-indicator and a means to measure carbon sequestration in sinks of grassy and herbaceous organs and in the soil that supports them.
Gases, such as carbon dioxide and methane, found in trace quantities in the atmosphere, absorb infrared energy and prevent such energy from leaving the atmosphere. Such gases are often referred to as "greenhouse" gases. Increasing levels of greenhouse gases in the atmosphere may therefore contribute to an increase in average global temperatures, resulting in adverse climate changes otherwise known as global warming. During the last century, human activities, such as burning fossil fuels, have increased the atmospheric levels of these so-called greenhouse gases.
Since 1800, atmospheric concentrations of CO.sub.2 have increased by more than 25%, primarily from the combustion of fossil fuels. For example, the burning of coal, oil and other organic-based fuels accounts for 99% of total CO.sub.2 emissions in the United States. In 1994, 1,529 million tons of carbon equivalent (MTCE) of CO.sub.2 were emitted as a direct result of fossil and organic-based fuel combustion. The other 1% of CO.sub.2 emissions is a by-product of non-energy related industrial practices. These include cement and lime production, limestone consumption, and soda ash production and use.
Over the last two centuries, the concentration of atmospheric methane has more than doubled. Although methane is second in quantity to CO.sub.2 as a greenhouse gas, methane is 24.5 times more effective in trapping heat or energy over a 100 year period. In 1994, 205 MTCE of methane were emitted in the United States. The largest sources are municipal solid waste landfills, which account for 90-95% of total landfill emissions. Currently, about 15% of landfill methane is recovered for use as an energy source. Roughly one-third of 1994 methane emissions came from agricultural operations. Topping the list of sources are enteric fermentation in domestic livestock and manure management. Approximately 27% of the 1994 United States methane emissions came from coal mining and petrol resources.
To solve the problem, at least two courses of action may be implemented: 1) reduce the rate at which greenhouse gases are discharged into the atmosphere; and 2) increase the rate these gases are cleansed from the atmosphere. Consequently, in response to concern regarding greenhouse gases and, pursuant to commitments made under the Framework Convention on Climate Change, the United States has undertaken efforts to reduce its greenhouse gas emissions. Rather than implementing a regulatory program, the Congress and President have called for voluntary action to reduce carbon emissions. The President's Climate Change Action Plan outlines a series of voluntary programs aimed at returning U.S. greenhouse gas emissions to 1990 levels by the year 2000 through reducing carbon emissions.
When considering the protocol for controlling carbon emissions, one may refer to the market-based sulphur dioxide (SO.sub.2) allowance trading component of the Acid Rain Program. The Acid Rain Program allows electric utilities to adopt the most cost-effective strategy to reduce SO.sub.2 emissions at generating units in their system. The Acid Rain Program Operating Permit outlines the specific program requirements and compliance options chosen by each source. Affected utilities are also required to install systems that continuously monitor emissions of SO.sub.2 and other pollutants in order to track progress, ensure compliance and provide credibility to the trading component of the program.
A parallel program to trade carbon credits may be patterned after the SO.sub.2 Allowance Trading System. The Administration recently proposed as yet unspecified emissions budgets that could be banked or traded among developed nations in order to reduce the levels of greenhouse gas emissions. According to the "Draft Protocol Framework," a procedure to ensure adequate reporting, measurement, review and compliance would need to be established. It would provide for "joint implementation" through which countries without emission budgets could create and transfer emission reduction credits, commonly called carbon credits, by those that do. A source of such carbon credits could be green plants or other photosynthetic organisms since they comprise a mechanism for cleansing or removing greenhouse gases from the atmosphere.
Using light energy from the sun, carbon from the air in the form of carbon dioxide and water in the soil, green leaves make sugar in a reaction called photosynthesis. A green plant can either use this energy for immediate growth or store it as starch for future use. Thus, plant growth, death and decay is a natural process which produces organic matter by removing carbon compounds from the atmosphere.
Organic matter is usually concentrated in the top few inches of many soils because most plant residue falls to the soil surface. Root decay also makes an important contribution to organic matter formation deeper in the soil. Soil formed under prairies or other grasslands, where roots are dense and evenly distributed through the top several feet, have a high concentration of soil organic matter. By definition, such organic matter is highly carbonaceous and represents conversion of atmospheric CO.sub.2 to organic matter in the soil.
Though photosynthesis by plants will convert atmospheric carbon compounds into organic soil material, agricultural practices may impact upon the efficiency of plant conversion. It has been known for many years that cultivation and crop production generally results in a decrease of soil organic matter. University research in Illinois, Missouri, Oklahoma and Oregon have all shown that organic matter levels in the soil will decrease significantly after 30-40 years of cultivation because microorganisms feed on crop residue and soil organic matter exposed by tillage and readily convert the agricultural organic matter into CO.sub.2 as an end product.
Also, plant residue from a previous crop is incorporated into the soil and gradually breaks down to form soil organic matter. Soil organic matter at this stage includes both plant and animal materials which contain large amounts of carbon. However, as a result of this decomposition, carbon dioxide builds up in soil air spaces and in solution with the soil. When the soil is tilled, a "burst" of CO.sub.2 is released into the atmosphere. Simultaneously, oxygen enters the soil and shifts the whole reaction process to enhance organic decomposition which is an undesirable result.
On the other hand, because air makes up only 25-30% of soil volume, there may be little oxygen to oxidize the stored carbon from such organic matter and release it back into the atmosphere as carbon dioxide. This process of fixing and storing atmospheric carbon in a sink such as vegetation or soil is called carbon sequestration, and the problem facing scientists and engineers is how to properly quantify the process and enhance the process from a quantitative viewpoint.
Promotion of the photosynthetic process is thus a desirable goal. To promote active growth, and thus the photosynthesis process, a forage plant must continually undergo a level of partial defoliation during its growing season in a manner which does not restrict root growth and which encourages leaf growth. Plants cannot photosynthesize optimally unless they have green leafy material above the ground to absorb sunlight. Cutting and removing older plant growth stimulates growth which permits increased, more photosynthetically efficient new growth and contributes to greater sequestration of carbon by the plant.
Also, partial defoliation of grassy and herbaceous plants stimulates the root system to grow optimally and encourages the growth of new green leafy plant material. The importance of this in the process of fixing carbon above and below the soil in plant tissue is that when the plant is growing vigorously, the plant removes more airborne carbon (i.e. carbon dioxide) and converts it to sugars and starches during the process of photosynthesis. Increased root mass and leaf surface, which is not shaded by mature, inefficient photosynthesizing plant material, allows the plant to photosynthesize more efficiently and to persist and grow during periods of environmental stress. Further, vigorously growing plants begin growing earlier during their growing season and continue growing later in the growing season thereby causing the plant to extract more carbon from the air and fix more carbon in above-ground and below-ground plant tissue, i.e. leaves, stems and roots. Partial defoliation of the plant to achieve optimal plant growth resulting in maximum carbon sequestration can be accomplished through the cutting, collecting and measurement of grassy and herbaceous crops on a predetermined schedule, or in other words, by providing a prescribed level of defoliation.
A problem, therefore, relates to the development of methods and apparatus to promote green plant growth efficiently and to measure, quantitatively, the growth in standard, universally accepted units.